[Prevalence of latent tuberculosis infection amongst immigrants entering prison]

To study the prevalence of latent tuberculosis infection (LTBI) and the predictive factors amongst immigrants entering prison.

prospective study conducted in May and June of 2009. The tuberculin skin test (TST) was performed, with induration of ≥ 10 mm being regarded as positive. Variables collected were: age, origin, number of incarcerations, length of time living in Spain, heroin and cocaine consumption, intravenous drug use and HIV infection. The rate of LTBI was calculated and the overall infection rate (ITL and history of TB). To study predictable factors, a bivariant and multivariant analysis were carried out using logistic regression.

152 male immigrants. Average age: 31.9 years ± 7.8; 37.2% of them with heroin or cocaine consumption and 7.5% IDU. 12 patients were previously TST positive and 6 patients had history of TB. TST was performed on 134 people, 63 with positive results and 71 with negative ones. ITL rate: 49.3. Overall infection rate: 53.3%. Bivariate associated with LTBI: more than one incarceration (67.4% vs. 36.4% in primary, p=0.001), age (76% ≥ 40 vs. 40.4% under this age and heroin and cocaine consumption (60% consumers vs. 39.3% non consumers; p=0.02. Multivariate analysis only confirmed the association with age (p=0.001; OR: 2.34, IC=1.39-3.94).

The LTBI rate amongst immigrants entering prison is very high. A complete study is recommended for all of them, with special attention being paid to the most vulnerable ones, such as older people.